iPhone games can run on iPad in full screen mode
An iPhone game developer, Kevin Ng, has used his game WordCrasher to test how it will look used on the recently revealed iPad
Using the SDK simulator he hit the 2x button to enlarge the game onto the screen. The result was loads of jaggy lines so he reworked the graphics for the full-screen which resulted in the “bump maps and other shader techniques” which are available with OpenGL ES 2.0.
“Apple is keen for us developers to create strong real world metaphors by simulating real world materials, objects and their behaviors," wrote Ng, which means that the screen is indeed as fast and responsive as Apple has totted.
This bodes well for games on it not looking like crap, which might raise it's prospects as a gaming device a bit more.
The whole process is described over on Ng's blog through here (via Wired), and it's a rather good read if you are into developmental topics.